Many people use mobile stations (i.e., client devices), such as cell phones and personal digital assistants (PDAs), to communicate with cellular wireless networks. These client devices and networks typically communicate with each other over a radio frequency (RF) air interface according to a wireless protocol such as Code Division Multiple Access (CDMA), perhaps in conformance with one or more industry specifications such as IS-95 and IS-2000. Wireless networks that operate according to these specifications are often referred to as “1×RTT networks” (or “1× networks” for short), which stands for “Single Carrier Radio Transmission Technology.” Another protocol that may be used is known as Evolution Data Optimized (EV-DO), perhaps in conformance with one or more industry specifications such as IS-856, Release 0 and IS-856, Revision A. Other protocols may be used as well, such as Global System for Mobile Communications (GSM), Time Division Multiple Access (TDMA), WiMax, and/or any others.
In a typical cellular wireless network, an area is divided geographically into a number of cell sites, each defined by a radio frequency (RF) radiation pattern from a respective base transceiver station (BTS) antenna. Each BTS antenna in a cell is in turn coupled with a base station controller (BSC), cooperatively defining a base station system. And the BSC is then coupled to or functionally integrated within a switch (e.g., a mobile switching center (MSC)) and/or gateway (e.g., a packet data serving node (PDSN)) that provides connectivity with a transport network such as the PSTN (public switched telephone network) or a public or private IP network (e.g., the Internet).
When a mobile station, such as a cellular telephone, pager, or appropriately equipped portable computer, for instance, is positioned in a cell, the mobile station communicates via an RF air interface with the BTS antenna of the cell. Consequently, a communication session can be established between the mobile station and another entity on the transport network, via the air interface, the BTS, the BSC and the switch or gateway. Such a communication session may be referred to as a “call,” whether the communication is a traditional voice “call” or a more advanced data session.